If x varies directly as y, and x = 7 when y = 10, find x when y = 4

Question

If x varies directly as y, and x = 7 when y = 10, find x when y = 4

Answer 1

Hi Chelsea,

 

When x varies directly with y, that means the relationship between x and y is of the form

 

   x = a * y

 

where "a" is a constant. We are given that when x=7, y=10; thus, we can write

 

   7 = a * 10, so a = 7/10 or 0.7

 

Now we can find the value of x when y=4 because we know a=0.7 and y=4; you substitute these into x = a * y and you have your answer ... give it a try.

 

Hope this helps you.